1. Field of the Invention
The present invention relates to a zoom lens system suitable for an electronic still camera.
2. Related Background Art
In a zoom lens system suitable for an electronic still camera, a zoom lens system whose first lens group is fixed, or a zoom lens system whose first lens group is movable has been known in Japanese Patent Application Laid-Open Nos. 6-281862 and 2003-177318.
However, in a zoom lens system whose first lens group is fixed, although the lens diameter of the first lens group can be small for focusing, it becomes difficult to make a zoom ratio large with securing high optical performance, so that the zoom ratio is about 5.7. Moreover, although the zoom ratio is tried to be made large abut from 7.6 to 9.7, aberration correction becomes insufficient in return for making the zoom ratio large, so that it becomes problem that optical performance deteriorates.
Moreover, in a zoom lens system whose first lens group is movable disclosed in Japanese Patent Application Laid-Open No. 6-281862, although optical performance is sufficient, the zoom ratio is small about from 1.9 to 3.7 and the half angle of view in the telephoto end state is about from 11.7° to 17.3° that is relatively large.
Furthermore, in a zoom lens system whose zoom ratio is made large by making the first lens group movable disclosed in Japanese Patent Application Laid-Open No. 2003-177318, although the zoom ratio is large about from 7.4 to 7.5 and the half angle of view in the telephoto end state is sufficiently small about from 4.6° to 4.7°, optical performance is not sufficient.